使用野生型秀麗線蟲-動物模式探討PM2.5之不良效應

Adverse toxicity of PM2.5 in a wild-type Caenorhabditis elegans

鍾孟靜(Meng-Ching Chung)

指導教授 ： 黃國林

國立屏東科技大學/工學院/環境工程與科學系所/博士(2020年)

https://doi.org/10.6346/NPUST202000161

摘要

近幾年來細懸浮微粒與PM2.5污染問題日益嚴重，對於人體的毒性危害也越來越受到重視，目前研究已證實暴露於PM2.5與心血管疾病、中風、心臟病與高血壓有關。而現今科學家長期關心在探討PM2.5有害空氣污染物（hazardous air pollutants, HAPs）對於人體健康所帶來之危害。本研究為使用動物模型-野生型秀麗線蟲（Caenorhabditis elegans , C. elegans）探討暴露PM2.5後所造成之不良效應，採集地點選自屏東縣-國立屏東科技大學（NPUST）、麟洛國中（LJSH）與台中市（traffic-related-air-pollutant, TRP）的交通要道與鄉村地區，同時進行多種毒性試驗，如：致死率（存活率試驗與壽命分析）、運動行為評估（頭部擺動與身體彎曲）與生殖毒性試驗（繁殖後代數量），來觀察不同地區之PM2.5對於秀麗線蟲之影響。根據2個地區採集之PM2.5濃度顯示，屏東縣2所學校皆符合標準，反之台中市採集之PM2.5濃度超過世界衛生組織與行政院環境保護署的法規標準值。在秀麗線蟲暴露實驗中的第一項研究結果顯示，暴露NPUST與LJSH的PM2.5皆對於存活率沒有顯著影響，但相對在壽命分析、運動行為評估與生殖毒性試驗方面，NPSUT所造成之毒性高於LJSH，因此PM2.5暴露濃度高低與線蟲之不良效應有顯著關係，另外長時間暴露所造成之毒性影響比急性暴露更加嚴重，透過這次實驗表明，雖然採集PM2.5濃度較低，但長期下來然仍可能會對周遭環境生物造成毒影響。
實驗結果亦顯示，急性暴露後並未對秀麗線蟲造成顯著致死影響在生殖毒性試驗方面，雖然Day A與Day C並未減少線蟲產生後代數量，但透過統計發現線蟲對於PM2.5劑量依賴性有顯著降低趨勢。根據運動行為評估（神經系統）與壽命分析，實驗結果發現 PM2.5濃度越高，對於線蟲神經毒性（頭部擺動與身體彎曲）與壽命影響也越顯著。與生殖毒性試驗結果相比，特定實驗對線蟲歲造成的毒性影響，如壽命分析與運動行為評估（神經行為）會更加嚴重。

關鍵詞：秀麗線蟲、細懸浮微粒(PM2.5)、交通排放之空氣污染物、壽命分析、運動行為評估、生殖毒性試驗與老化現象。

關鍵字

秀麗線蟲 ； 細懸浮微粒(PM2.5) ； 交通排放之空氣污染物 ； 壽命分析 ； 運動行為評估 ； 生殖毒性試驗與老化現象

並列摘要

Fine particulate or PM2.5 has raised the public concern due to its toxicity to human. PM2.5 pollution is linked into cardiovascular disease, stroke, heart attack, and hypertension in science. Many environmental scientists have focused on PM2.5-bounded hazardous air pollutants (HAPs) and their toxic effects correlated to human health. In the present study, an in-vivo wild-type Caenorhabditis elegans (C. elegans) was used to examine the induced toxicity after C. elegans was exposed to PM2.5. Many PM2.5 toxicity assessments using in vitro nematodes’ models have focused on PM2.5-bounded hazardous pollutants. The study design of the in-vivo models were addressed to PM2.5 toxicity in the rural and traffic areas in Pingtung and Taichung, respectively. Firstly, the toxic effects of outdoor PM2.5, collected from National Pingtung University of Science and Technology (NPUST) and Linluo Junior High School (LJHS), Pingtung, Taiwan, on nematode C. elegans were investigated. PM2.5 from NPUST and LJHS, which did not meet the standard. Secondly, the toxicity of traffic-related-pollutant (TRP) PM2.5 was evaluated in the animal model C. elegans using different toxicological endpoints such as lethality, survivability (lifespan or ageing), behavioral (head thrashing and body bending), and reproduction (brood size). Most TRP PM2.5 concentrations collected in Taichung were exceeded the standards of Taiwanese Environmental Protrction Adminstration and World Health Organzation guidline.
No significant PM2.5 lethality on C. elegans was observed for the NPUST and LJHS samples in acute toxicity tests. The PM2.5 from NPUST exhibited higher toxicity to lifespan, locomotion, and reproduction in the C. elegans animal models than that from LJHS; therefore, adverse effects could be correlated with PM2.5 concentrations. Prolonged exposure to PM2.5 led to more severe toxicity in nematodes as compared to acute exposure.Therefore the long-term adverse effects of ambient PM2.5 on environmental organisms should be carefully considered even when PM2.5 is at low levels.
No immediate lethality was observed after acute exposure of the nematodes. On the other hand, sublethal endpoints of reproduction exhibited statistically significant dose-dependent reduction, although Day A and Day C did not decrease the egg-laying capability of the worms. For the neurological toxicity, it is inferred that the higher the PM2.5 concentrations, the more the adverse effects of neurobehavior (head trashing and body bending) it poses on the C. elegans. The lifespans of nematodes exposed to heavily TRP PM2.5 were significantly shortened compared with those of untreated ones based on survival rate. The nematodes exposed PM2.5 models not only posed potentially adverse health effects on human but also represented ecotoxic impacts on the ecosystem. Accordingly heavy concentrations of TRP PM2.5 significantly and severely disrupted toxicological endpoints of neurology and reproduction to C. elegans. TRP PM2.5 significantly shortened the lifespan of the nematodes compared with the control. TRP PM2.5 might more severely influenced the specific toxic endpoints, such as lifespan and neurobehavira, in this in-vivo models compared with the reproductive endpoints. C. elegans animals model is a sensitive one for the evaluation of PM2.5 ecotoxicity.

Keywords: C. elegans; PM2.5; traffic related pollutant (TRP); lifespan; locomotion; reproduction; ageing.

並列關鍵字

C. elegans ； PM2.5 ； traffic related pollutant (TRP) ； lifespan ； locomotion ； reproduction ； ageing

參考文獻

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